1. Field of the Invention
The present invention generally relates to an electronic component, and more particularly to an assembly including an electromagnetic relay and a circuit board on which the electromagnetic relay is mounted.
2. Description of the Related Art
FIGS. 2A and 2B show an example of a conventional electromagnetic relay, wherein FIG. 2A is a front view and FIG. 2B is a side view as seen from arrow II of FIG. 2A. The illustrated conventional electromagnetic relay includes a holder 50 usually formed as a molded member and various components held on the holder 50. The conventional electromagnetic relay typically includes a cover (not shown) attached to the holder 50 so as to enclose the holder 50 and the various components, but FIGS. 2A and 2B illustrates a state where the cover is removed.
The illustrated conventional electromagnetic relay includes a coil (not shown) held in a coil housing section 51 of the holder 50 and coil terminals 52, 53 connected respectively to the wire ends of the coil. The electromagnetic relay further includes a movable contact 57 and a stationary contact 59. The movable contact 57 is capable of being mechanically displaced via a driving mechanism 55 by magnetic force generated by the coil. The stationary contact 59 is capable of being switched between a contact state and a noncontact state with respect to the movable contact 57 due to the displacement of the movable contact 57 under the excitation of the coil. The movable contact 57 and the stationary contact 59 are respectively attached to the first ends of contact members, and terminals 61 and 62 for external connection are respectively formed at the second ends of the contact members.
Typically, it is necessary that the coil has a certain length to generate sufficient magnetic force, and that a desired distance is ensured between the movable contact 57 and the stationary contact 59 in the noncontact state for reliable electrical disconnection, and thereby the electromagnetic relay tends to increase in dimensions. In the example shown in FIGS. 2A and 2B, the electromagnetic relay has a substantially rectangular parallelepiped body and the dimensions thereof are considerably large, particularly in upward/downward and rightward/leftward directions in FIG. 2A.
In the electromagnetic relay of FIGS. 2A and 2B, the terminals 52, 53, 61 and 62 for external connection protrude straight from and extend perpendicularly to a bottom surface 54 of the body, which has a relatively small area. According to this arrangement, the electromagnetic relay of FIGS. 2A and 2B can be mounted on a circuit board (not shown) in an orientation such that the bottom surface 54 having the relatively small area is opposed to the surface of the circuit board, and as a result, an area used for mounting the electromagnetic relay in the surface of the circuit board can be reduced.
On the other hand, depending on the configuration of an apparatus in which the electromagnetic relay is installed, it may be necessary to reduce the height of the electromagnetic relay defined in a direction orthogonal to the surface of the circuit board, i.e., to configure the electromagnetic relay to have a low-profile shape. In this case, as shown in FIG. 3, an alternative arrangement is conventionally used, in which the terminals 52, 53, 61, 62 for external connection are bent at right angles in a thickness direction of the plate-like materials thereof so as to extend parallel to the bottom surface 54. In this alternative arrangement, the terminals 52, 53, 61, 62 are provided respectively with distal portions extending beyond a lateral surface 56 of the rectangular parallelepiped body, the lateral surface 56 intersecting perpendicularly with the bottom surface 54, and thus the electromagnetic relay can be mounted on the circuit board in an orientation such that the lateral surface 56 is opposed to the surface of the circuit board. In this connection, FIG. 3 shows a cover 58 attached to the holder 50 to define the rectangular parallelepiped body.
As another countermeasure, Japanese Unexamined Patent Publication (Kokai) No. 2002-184286 (JP2002-184286A) describes an electromagnetic relay capable of being connected to an external terminal without requiring a large space in a height direction. The electromagnetic relay of JP2002-184286A includes a rectangular parallelepiped body having mutually opposite first and second lateral surfaces and a bottom surface, and a plurality of L-shaped terminals protruding outward from the bottom surface of the body, in which some terminals have distal portions extending beyond the first lateral surface and remaining terminals have distal portions extending beyond the second lateral surface. The electromagnetic relay can be mounted on a circuit board in an orientation such that the bottom surface of the body, from which the terminals protrude, is opposed to the surface of the circuit board, and in this orientation, the distal portions of the terminals can be connected to the external terminals provided on the circuit board, so that the overall height of the electromagnetic relay mounted on the circuit board can be reduced.